Investigation of Stability of Noncircular Lobed Journal Bearings Lubricated by Ferrofluid

Nowadays, the demand for journal bearings operating at high speeds and also the importance of their stability in practical usage has caused a need for noncircular lobed bearings instead of circular bearings. This makes the extreme effects of lubrication kind in bearing performance more important. For this reason, choosing appropriate lubricant is of great significance. Ferrofluids as a result of having unique features can be considered as one of the choices. The aim of this paper is to study the stability of two, three and four lobe noncircular journal bearings lubricated with ferrofluids considering parameters such as eccentricity ratio, the ratio of length to diameter and also the magnetic force coefficient. In this work, the numerical method of finite elements is used to solve the equations. The results show that by increasing the eccentricity ratio and the length to diameter ratio and also by decreasing the magnetic force coefficient, bearing stability increases. As well as, by increasing the number of lobes in noncircular lobed bearings, it is possible to get more stability range.